Motor control system and switch



March 11, 1952 c. R. PETER MOTOR CONTROL SYSTEM AND SWITCH Filed April 19, 1946 INVENTOR ATTORNEY JJWMAM IPS? RWM. 4 .miaina 111-141. al: i

Patented Mar. 1l, 1952 UNITED STATES PATENT OFFICE Charles R. Peter, Milwaukee, Wis., assigner to Allis-Chalmers Manufacturing Company, Milwaukee, Wis., a corporation of Delaware Application April 19, 1946, Serial No. 663,374

5 Claims. l

This invention relates to motor control systems and switches, and more particularly to systems and switches for controlling an electric motor for starting an engine; and the principal object of the invention is the provision of new and improved control systems and switches of these types.

A more specic object of the invention is the provision of a control switch embodying means for preventing closure thereof due to mechanical shock, vibration or the like.

Another object of the invention is the provision of means whereby the main control contacts will be moved to open position if they remain closed after an electroresponsive means for actuating them to closed position has been deenergized, and more specifically, automatically to apply a hammer blow to force the main control contacts apart if they have become frozen Other objects will appear as the description of the invention proceeds.

The novel features of the invention will appear from this specication, and the accompanying drawing, showing one embodiment of the invention, and forming a part thereof, and all of these novel features are intended to be pointed out in the claims.

In the drawing, Fig. 1 is an electrical diagram of a control system embodying the invention, the

main control switch embodied therein being also shown diagrammatically;

Fig. 2 is a longitudinal sectional view of a main control switch embodying the invention, on the line II-II of Fig. 3;

Fig. 3 is a front elevation of the control switch shown in Fig. 2;

Fig. 4 is a bottom view of a detail, on an enlarged scale; and

Fig. 5 is a side View of the detail shown in Fig. 4, looking from the plane V-V in the direction of the arrows.

Referring rst to Fig. 1, the motor I to be controlled is here shown as comprising an armature I I and a series field winding I2, The motor I0 is adapted to start an engine (not shown). The motor Ill is controllable by a main electroresponsive control switch I3 shown as including relatively stationary contacts I4, I which may be bridged by a relatively movable contact I6. conductor I'I to one terminal of a source here shown as a battery I8, the other terminal oi the battery being connected 'by a conductor |79 in one terminal of the motor I0. The other terminal oi the motor ID is connected by a conductor `2|) to the switch contact I5,

The switch contact I4 is connected by a y The electroresponsive switch I3 is here shownv as comprising a winding 2| which, when energized, is adapted to lift an armature 22. The armature 22 may be in the form of a clapper or core, or a combination of a clapper and core as will appear. The armature 22, when lifted, causes the movable contact I 6 to engage the stationary contacts I4, I5, there being any suitable operative connection, such as a rod or plunger 23, between the armature 22 and the contact i5.

The switch I3 further includes a winding 24 which, when energized, is adapted to pull an armature 25 downwardly. As shown in the diagram Fig. 1, the armature 25 is directly connected to the armature 22 by a downward extension of the plunger 23, but, as will appear hereinafter, preferably the connection is not direct but through lost motion.

For the purpose of controlling the electroresponsive switch I3, a master control switch 25 is provided. The control switch 26 is here shown as including a movable contact 2l which, desirably, is biased to the position shown where it normally bridges a pair of contacts 28, 29. When i the contact 2l is moved away from its normal position, it is adapted to bridge a pair of contacts 30, 3|, the contact 21 being then out of engagement with the contacts 28, 23.

One terminal of the winding 2| is connected by a conductor 32 to the contact 3|. The other terminal of the winding 2| is connected by a conductor 33 to the conductor I'I and hence to a terminal of the battery I8. The contacts 28, are connected to a conductor 34 in turn connected to the conductor I 9 and hence to the other battery terminal.

One terminal of the Winding 24 is connected by a conductor 35 to the contact 29. The other terminal of the winding 24 is connected to the plunger 23 through a flexible conductor 6| as will more fully appear. Fuses 36 may be interposed in the conductors 32, 35.

Referring now to Figs. 2 through 5, the electroresponsive switch I3 comprises a casing having a cylindrical portion 31 of non-magnetic material with a top cover 38 and a bottom cover 39, suitable gaskets being interposed between the covers and the respective ends of the cylindrical portion 31 to make the joints water tight. The covers 38, 39 may be of any suitable material and are held in place in any suitable way.

The winding 2| is here shown as of annular form Iand provided with a yoke 40 of magnetic material. The yoke lli),` as here shown, Yincludes a cylindrical kouter wall 4| and a hollow fcylindrical core 42 joined at the top by an annular ward from a hollow cylindrical core 51.

portion 43. The cylindrical wall 4I is shown as fitting in the casing wall 31 and is held therein in any suitable way.

Current may be fed to the winding 2i in anir suitable way. In this instance spring pressed contacts 45, 45, which extend through openings in the casing portion 31 and the wall 4I,- are adapted to make contact with terminal contact plates carried by and connected to the ends of the winding 2i. The contacts 45, 45 are supported in metallic sockets in turn supported by an insulating member 45, fastened water tight in any suitable way to the casing portion 31. The sockets which support the contacts 44, 45 are respectively provided with connection means 41, 43 to which the conductors 32, 33 (Fig. l). may be connected.

Armature 2 2 is here shown as comprising an annular disk 49 extending radially outward from a hollow cylindrical core 55. The core 59 is slidable in the core 42 and, desirably, a sleeve 82 of nen-magnetic material is interposed between the core 55 and the inside of the core 42, and the sleeve may be formed at its lower end with a iange 53 so that the disk 49 cannot come into direct contact with the lower end of the core 42.

The armature 22 is carried by the plunger 23 in fixed relation thereto and insulated therefrom. Fitting over the plunger 23 is an insulating sleeve I having a collar 52 engaged by the upper end of the core 55. rihe lower side of the disk 49 engages insulating members 53, held in place by a bolt and nut 54, the bolt being disposed through registering holes in the members 53, the sleeve 5i and the plunger 23.

The winding 24 is shown as annular and as provided with a yoke 55 analogous to the yoke 45, but in this instance the yoke 55 has its Open end directed upwardly. The yoke 55 fits in the casing portion 31 and is suitably fastened therein. The armature'25 is here shown as comprising an annular disk 55 extending radially out- The core 51 is slidable in the core of the yoke 55 and, desirably, anon-magnetic sleeve is interposed, the sleeve 52 having an outward ange 83 at its upper end to prevent direct contact between the underside of the disk 55 with the upper'end of the core of the yoke 55.

The core 51 is also slidable with respect to the plunger 23, being slidable on the insulating sleeve 5I. The core 51, and hence the armature 25, is biased upwardly by a spring 58 at itsupper end engaging a recess in the core 51 and at its lower end engaging an insulating collar 59 on the plunger 23. The spring 58 normally maintainsdesired lost motion between the lower end of the core 51 of the armature 25 and the upper side of the collar 59. The collar 59 has a hole which lits the plunger 23 and a recess in its upper end in which the lower end of the insulating sleeve 5i engages. The lower end of the collar 5S abuts a collar 59 on the lower end of the plunger 23. The plunger 23 is electrically connected, by a flexible conductor 5I, tc a terminal 52 in turn connected to an end of the Winding 25. The other end of the winding 24 is connected to a plate engageable by a spring pres-sed Contact 53 extending through openings in the casing portion 31 and the outer wall of the yoke 55, the contact G3 being carried in a socket in turn carried by the insulating block 46. The socket which supports the contact 53 is provided with connection means 64 to which the conductor 35 (Fig. 1) may be connected.

The contact I6 is here shown as comprising a bridging member 65 carrying contacts 55, 61 which, when the bridging member 65 is moved upwardly, are adapted to engage the contacts I4, I5 respectively. A stud 68 having a head at its upper end, is screw threaded at its lower end into the upper end of the plunger 23. The head of the stud 68 bears against the upper side of the bridging member 55, the shank of the stud 68 passing freely through a hole in the bridging member. The bridging member 65 is biased against the underside of the head of the stud E5 by a spring 69'.

The plunger 23, and hence the armature 22, is biased downwardly by a spring 15 which at its upper end engages the under side of the cover 38 and at its lower end engages the upper end of the collar 52. An insulating bushing 84 may be provided within the spring 19 to keep it out of contact with the plunger 23.

The contacts I4, I5 are desirably supported by a cover 1I, of any suitable material, suitably fastened, water tight, to the cover 38. The contacts I4, I5 are carried by terminal studs extending through and insulated from the cover 1I and are provided with connection means 12, 13 to way. Each member 14 is made of non-magnetic material riveted or otherwise suitably fastened to an end of a pivoted lever 15, of magnetic material, here shown as generally arcuate. Each lever 15 is pivoted intermediate its ends on a pivot 16 carried by an annular plate 11 of nonmagnetic material. The plate 11 is positioned at the under side of the coil 2l and fastened in position in any suitable way.

Each lever 15 is biased to the position shown in Fig. 4 by a respective tension spring 18 engaging the lever 15 at one end and engaging a pin 19, carried by the plate 11, on the other end. In this position of the parts each blocking member extends over lower end portions of the wall 4I of the yoke 49. Therefore, assuming that the switch I3 was mechanically shocked or jarred in such a way as to move the armature 22 toward the winding 2l, the armature would be stopped from upward movement by engagement ofV the upper, outermost surface portion of the disk 49 with the blocking members 14. Such upward movement of the armature 22 as may be permitted by the blocking members 14 is not sumcient to cause the plunger 23 to lift the contacts 66, 61 into engagement with the contacts I4, I5.

On the other hand, if the winding ZI is energized, each lever 15 will be turned clockwise, against the bias of the respective spring 18, by reason of the shunt path for magnetic flux across the lower ends of the yoke parts 4I, 52, through the levers 15. Hence the blocking members 14 will be drawn generally radially inwardly. The disk 49 may accordingly move upwardly sufiiciently to cause bridging of the contacts I4, I5, the blocking members 14 having meanwhile assumed a position in a recess 89 formed in the upper side of the disk 49. It will be understood that the recess is made deep enough so that when' the levers have moved the blocking members 14 radially inward, the -under sides of the block-.- ing members will not interfere with the desired lift of the disk 49. In order to insure that the lever 15 will be rotated clockwise, to withdraw the blocking member 14 inwardly, the lever 15 is so constructed and arranged that in the position of the parts shown in Fig. 4, that end of the lever which carries the blocking member 14 is closer to the adjacent part of the core 42 than it is to the adjacent part of the wall 4I, and the other end vof the lever is closer to the adjacent part of the wall 4| than it is to the adjacent part of `the core .42,

Desirably, a pin 8| carried by the bushing 59 tand lslidably engaging in a longitudinal slot in the inner wall of the core of the yoke 55 is provided to prevent turning of the plunger 23.

The operation of the apparatus as a whole is as follows. Assuming that the parts are in the position shown on the drawing, and that it is desired to start the engine drivable by the motor I9, the master control contact l21 is moved so that it engages the contacts 30, 3| This closes a circuit for the winding 2| from the battery I8; the winding 2| is energized and, as hereinbefore set forth, the blocking members 14 are moved to permit the armature 22 to lift the plunger 23 against the bias of the spring 10. As a result the contacts 66, 61 are caused to engage the contacts I4, I5. The biasing spring 69 permits resilient engagement of the contacts since the plunger 23 and the stud 68 may move upwardly somewhat after the contacts have come into initial engagement. The head of the stud 63 will then be somewhat above the upper side of the bridging member 65.

The motor I ll then is fed with current from the battery I8, and the contact 21 is held closed long enough to permit the motor to start the engine. It will be noted that while the contact 21 is in engagement with the contacts 3U, 3 I, any possible circuit through the winding 24 is interrupted. It will be further noted that when the plunger 23 is lifted, the spring 58 maintains the armature 25 lin engagement with the members 53, so that the plunger '23 lifts the armature 25 upwardly, away from the winding 24 and its yoke 55.

Under normal conditions, if the master control switch contact v21 is permitted to open (the engine having been started), the winding 2| will be deenergized and the armature 22 and the plunger 23 will drop thereby opening the circuit of the motor IG. If, however, excessive current conditions or the like should have caused the contacts 66, 61 of contact I6 to freeze to the contacts I4, I5. the plunger 23 will not drop when the winding 2l is deenergized and the motor circuit will not be opened. The invention provides against this contingency. Assuming that the contact I6 is frozen in closed position, and that the master control switch contact 21 has assumed its normal position in which the contacts 29, 29 are bridged, a circuit is established from the battery I8 through conductor I1, contact I4, contact I6, through the plunger 23, the nexible conductor 6 I, the winding 24, the conductor 35, the contacts 29, '21, 28, the conductor 34 to the other terminal of the battery.

Energization of the winding 24 causes the armature 25 to be forcibly moved downwardly against the bias of the spring 59, taking up the lost motion between the lower end of the core 51 and the top of the collar 59, thereby delivering a hammer blow to the collar 59. The force of the hammer blow acts downwardly on the plunger v23 and causes the kContact I6 to break away from the contacts I4, lI5, thus opening the circuit of the motor I0. `It will be evident that disengagement of the contact I6 from the contact I4 interrupts the circuit of the winding 24, so that the parts are again in normal condition in readiness for the next operation.

From the lforegoing vit will be apparent to those skilled in vthe art that the illustrated embodiment of the linvention provides a new and improved motor control system and switch and accordingly accomplishes the objects of the invention. On the other hand, it will also be obvious to those skilled in the art tha-t the illustrated embodiment of the invention may be variously changed and modified, or features thereof. single or collectively, embodied in other combinations than those illustrated, without departing from 4the spirit of the invention, or sacrificing all of the advantages thereof, and that accordingly the disclosure herein is illustrative only, and the invention is not limited thereto.

It is claimed and desired to secure by Letters Patent:

l. An electromagnetic switch, comprising: relatively stationary contact means and relatively movable contact means engageable therewith; means, including a first Ywinding and a rst armature normally positioned away from said winding, constructed and arranged to cause engagement of said contact means by movement of said armature toward said winding upon energization thereof a second winding and a second armature normally disposed near said second winding; `and means responsive to said engagement-causing movement of said first armature for moving said second armature away from said second winding and for moving said i'irst armature away from said rst winding with a hammer blow upon energization of said second winding.

2. An electromagnetic switch, comprising: relatively stationary contact means and relatively 5 movable contact means engageable therewith; a

first winding and a first armature normally disposed away from said first winding; means, including a plunger actuatable by said nrst armature, constructed and arranged to cause engagement of said contact means by movement of said armature toward said winding upon energization thereof; a second winding and a second armature normally disposed near said second winding; and means, including a lost motion connec- 55 tion between said plunger and said second armature, so constructed and arranged that said engagement-causing movement of said rst armature moves said second armature away from said second winding without taking up said lost motion and upon energization of said second winding said lost motion is taken up and a hammer blow is delivered to said plunger to positively disengage said contact means.

3. An electromagnetic switch, comprising: rel- 05 atively stationary contact means and relatively movable contact means engageable therewith; a rst winding and a rst armature normally disposed away from said rst winding; means, including a plunger actuatable by said rst armature, constructed and arranged to cause engagement of said contact means by movement of said arma-ture toward said winding upon energization thereof; a second winding and a second armature normally disposed near said second winding, said second armature being carried by s aid plunger and slidable with respect thereto; and operating means so constructed and arranged.v that said engagement-causing movement of said first armature moves said second armature away from said second winding, said operating means comprising a lateral projection on said plunger engageable by said second armature, and a spring for biasing said armature to a position substan tially spaced from said lateral projection, energization of said second winding causing said second armature to engage said lateral projection with a hammer blow.

4. An electromagnetic switch, comprising: relatively stationary contact means and relatively movable contact means cooperable therewith; a winding; a yoke of magnetic material for said winding, including a cylindrical portion adjacent the outer periphery of, said winding and having a free end; means, including an armature, constructed and arranged to cause said relatively movable contact means to engage said relatively stationary contact means upon energization of said winding, said armature being of disk shape spanning said free end; and blocking means, responsive to energization of said winding, constructed and arranged to prevent said armature from causing said relatively movable contact means from engaging said relatively stationary contact means unless said winding is energized, said blocking means including a blocking member interposed between an outer portion of said armature and said free end when said winding is deenergized, and means for withdrawing said blocking member in a generally radially inward direction with respect to said winding from between said outer portion and said end in response to energization of said winding. said armature having a recess for accommodating said blocking member when so withdrawn;

5. An electromagnetic switch, comprising: a relatively stationary contact and a relatively movable contact engageable therewith, a first winding, a member of magnetic material disposed adjacent the outer peripheryof said iirst winding and having a free end, means including a first armature normally positioned away from said first winding constructed and arranged to cause engagement of said contacts upon energization of said iirst winding, said armature having a portion in approximate alignment with said free end, blocking means, responsiveto energization of said first winding, constructed and arranged to prevent said armature from causing engagement of said contacts unless said rst winding is energized, said blocking means including a blocking member interposed between said portion and said free end when said first winding is deenergized, means for withdrawing said blocking member from between said portion and said free end in response to energization of said iirst' winding, a second winding and a second armature normally disposed near said second winding, and means responsive to said engagement-causing movement of said rst armature ior moving said second armature away from said second winding and for moving said iirst armature away from said first winding with a hammer blow upon energization of said second winding.

CHARLES R. PETER.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 653,685 Maxim July 17, 1900 967,192 Hawkins Aug. 16, 1910 982,146 Larzelere Jan. 17, 1911 1,291,039 Lowenstein et al. Jan. 14, 1919 1,742,875 Quick et al. Jan. 7, 1930 1,878,777 Horn Sept. 20, 1932 1,912,669 Trail June 6, 1933 1,946,132 Dawe Feb. 6, 1934 1,968,385 Gille July 31, 1934 2,027,064 Rozumek Jan. 7, 1936 2,062,345 Wilhelm Dec. l, 1936 2,090,522 Sippel Aug. 17, 1937 2,140,229 Hipsley Dec. 13, 1938 2,358,648 Lafite Sept. 19, 1944 2,476,794 Austin July 19, 1949 

